NEW DELHI The Supreme Court on Wednesday allowed one of two Italian marines facing murder charges over the deaths of two Indian fishermen to stay in his home country until April 30 following heart surgery.

The decision defuses a possible judicial standoff after an Italian senator said the day before that Massimiliano Latorre would not return to face trial as he had been due to by this Friday, having earlier been allowed home for medical treatment.

"We allow him to stay in Italy until April 30 on health grounds," a three-judge bench of India's highest court said in its order.

The Supreme Court set a hearing on April 13 to take up the case of the marines, who stand accused of killing two Indian fishermen off the Kerala coast almost four years ago.

They were part of a military security team protecting an Italian oil tanker and say they mistook the fishermen for pirates.

The Italian government, which is at loggerheads with India over the case, said the Indian court could not make any decisions regarding Latorre before an international arbitration hearing at The Hague that it has requested

The International Tribunal for the Law of the Sea in Hamburg ordered India to suspend legal action against Latorre and the second sailor on trial, Salvatore Girone, pending the hearing.

"(Latorre) can therefore stay in Italy for the entire duration of the international arbitration process," Italy's foreign ministry said in a statement.

Girone is still at the Italian embassy in New Delhi.

The fallout from India's arrest of the marines has damaged wider relations between Italy and India, contributing to the collapse of a European Union-India summit last year.

Prior to Latorre's return, outrage among Italians at the pair's imprisonment was writ large on banners, suspended from prominent buildings in some city centres, that read "We will bring the marines home".

In another case this week, a court in Tamil Nadu sentenced 35 crew members of a private American ship - 25 of them foreigners - to five years in jail for illegal possession of arms in Indian waters.